Recently, ten European cities have received the seal of the 'EU Mission for Smart and Climate Neutral Cities', one of the EU Missions in 'Horizon Europe'. This label recognizes cities' plans to achieve climate neutrality by 2030. We use this recent award to bring together young Europeans and discuss urban sustainability, the impact of cities on the environment, adaptation of cities to Climate Change and other topics, such as promotion of public transport. But we don't stop there, and since environmental problems are global, we leave the scope of cities to discuss other issues such as plastic pollution, Climate Change, the impact of transportation, etc. We also try to provide participants with tools for public participation, we review some examples of successful campaigns from history, we teach them tools for group management and we review the current policies of the European Union regarding the environment. Regarding young people, we hope that participating in this exchange will help them to have a more in-depth vision of current environmental problems, and more specifically, the impact and solutions that cities can offer to these problems. Likewise, we hope that the exchange experience will be enriching for the participants, coming into contact with young people from other parts of Europe and creating lasting friendships, thus strengthening the feeling of European belonging. On the other hand, we hope that the experience will help young people to have an international travel experience, the first in many cases, and will serve to bring together young people from different backgrounds and socioeconomic characteristics.